/*
 * Copyright 2012 Marsrutai.lt
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package lt.marsrutai.mobile.android.intercept;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class InterceptorProxy implements InvocationHandler {

    private Object object;
    private Interceptor interceptor;

    public static Object newInstance(Object object, Interceptor interceptor) {
        return Proxy.newProxyInstance(object.getClass().getClassLoader(), object.getClass().getInterfaces(), new InterceptorProxy(object,
                interceptor));
    }

    private InterceptorProxy(Object object, Interceptor interceptor) {
        this.object = object;
        this.interceptor = interceptor;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Object result = null;

        try {
            result = interceptor.interceptBefore(method, args);

            if (null == result) {
                result = method.invoke(object, args);
                interceptor.interceptAfter(method, args, result);
            }
        }
        catch (InvocationTargetException e) {
            throw e.getTargetException();
        }
        catch (Exception e) {
            throw new RuntimeException("Unexpected invocation exception in InterceptorProxy. " + e.getClass().getName() + ": " + e.getMessage(), e);
        }

        return result;
    }
}
